Mineral fillers are probably the most widely used additives in thermoplastic resins. Commonly used mineral fillers include talc, wollastonite, clay and mica. These materials are typically employed for economic reasons, i.e., to reduce the cost of relatively high priced resins, and/or to impart a particular property to a resin; e.g., enhancement of specific properties such as impact strength, co-efficient of linear thermal expansion, tensile strength, tensile modulus, and flexural modulus. Use of mineral fillers in thermoplastic resins, with the concomitant improvement of properties described above can result in important improvements to articles manufactured using these resins such as reduced warpage in molded parts and articles fabricated from these formulations. The main challenge from a property balance perspective is to achieve high impact and toughness values in conjunction with stiffness and tensile strength properties as well as surface properties, e.g. splay, since these typically tend to go in opposing directions.
Accordingly, it would be beneficial to provide blended polycarbonate compositions comprising a mineral filler that have improved impact properties while retaining other desirable properties such as surface properties, particularly splay.